The present invention relates to an occupant protection device, such as an airbag, for protecting an occupant when an impact load is acted on a vehicle, and, in particular, to one type of airbag which is expanded along a side window to protect an occupant""s head and to prevent the occupant from being thrown out of a compartment of the vehicle.
Heretofore, as to such a occupant protection device of a vehicle, there has been known a device, for example, disclosed in Japanese Patent Laid-open Publication No. Hei 10-166988, in which a longitudinally extendable airbag is folded and the folded airbag is housed along a front pillar and a roof side frame to be expanded downward along a side window in the form of a curtain when an impact load is acted on a side of a vehicle.
In the device described above, a front end of the airbag is connected to a lower side of the front pillar of the vehicle, while its rear end is connected to an upper side of a quarter pillar. The airbag is also divided over the front end to the rear end into a plurality of small bags (expanding portions) which may extend approximately vertically with having respective cylinder shapes, i.e. a curtain-like shape as a whole, in the expanded condition of the air bag. Expanding these plurality of small bags respectively makes the airbag shorten in the longitudinal length as a whole. This results in a tension in the longitudinal direction to enable the airbag to restrain a head or the like of an occupant.
Further, among the plurality of small airbags in this conventional airbag described above, the small bags disposed rearward with respect to a center pillar of the vehicle are adapted to have particularly large size in diameter than others. This may improve the restraint performance to an occupant because, for example, when an occupant""s head which is moving toward outside of the compartment is restrained by the airbag, the small bags having larger diameter may be caught by the center pillar to control a displacement of the airbag.
However, since the conventional airbag is made by sewing to divide it into the plurality of small bags, there is a problem that a shock absorbing performance cannot sufficiently be obtained in the vicinity of seams of the airbag and an overall occupant protection performance is also lowered. In addition, since a strength of the airbag is lowered in proportion to increased seams, there is the possibility that the seams is torn during its expansion, resulting in deterioration of the occupant protection performance.
Further, in addition to a sewing operation for making such an airbag, it is also necessary to apply an sealant to the seams for preventing a expansion gas from leaking through the seams. This additional measure requires significant labors and times, and results in remarkably increased manufacturing cost.
In view of the problems described above, the present invention was made. An object of the present invention is to enhance the occupant protection performance and the cost reduction through means of reducing seams of an airbag with maintaining the occupant restraint performance by exercising ingenuity in a structure for giving a tension in the longitudinal direction to the airbag during its expansion, in a curtain type airbag expanding to cover an inside of a side window when an impact is acted on a vehicle.
Another object of the present invention is to improve the curtain airbag type of occupant protection device described above by means of introducing a new layout in a expansion of the airbag so that the impact load at the time when the occupant secondarily collides with the rear pillar disposed on the rear side of the window can be absorbed to surely protect the occupant.
To achieve the aforementioned object, the present invention provides connecting members for connecting front and rear ends which are located at a lower portion of an airbag to a body of a vehicle body respectively, and a slack absorbing device applied to at least one of the connecting members for absorbing a slack of the connecting members in the expanded condition of the airbag.
In particular, according to one aspect of the present invention, there is provided an occupant restraint equipment of a vehicle on the presumption that the vehicle includes a front side pillar and a rear side pillar disposed on front and rear sides of a side window of the vehicle respectively, and a roof side rail longitudinally extended to connect respective upper ends of the both pillars each other, and the occupant protection device includes an airbag which is folded and housed in the range from the front side pillar to the rear side pillar through the roof side rail so that the airbag is expanded to cover an inside of the side window when an impact load is acted on a side of the vehicle. Thereat, the occupant restraint equipment of the present invention comprises an upper edge of the airbag fixed to at least the roof side rail, a front connecting member for connecting a front lower end of the airbag to a body of the vehicle positioned frontward more than the side window, a rear connecting member for connecting a rear lower end of the airbag to a body of the vehicle positioned rearward more than the side window; and a slack absorbing device attached to at least one of the front and rear connecting members for absorbing a slack in the connecting members in the expanded condition of the airbag.
According to the aforementioned structure, the airbag primarily housed in the roof side rail of the vehicle is extended downward to cover the inside of the side window when an impact load is acted on the side of the vehicle. On this way, the folded airbag is extended downward as a whole, and a slack of the connecting members fixed to the lower side of the airbag is absorbed by the slack absorbing device, so that the front and rear connecting members may provide a sufficient tension to the air bag by longitudinal pulling of the connecting members. Thus, it is no longer required to divide the air bag into a plurality of small bags as the conventional airbag. This enables to decrease the seams of the airbag to which an occupant would be contacted in the expanded condition of the airbag, and so the occupant protection performance can be improved. In addition, the manufacturing cost can be reduced due to the reduced seams.
According to a preferred embodiment of the invention, the slack absorbing device may include an expanding portion which is formed in at least one of the front and rear ends of the airbag and is expanded in the expanded condition of the airbag, and at least one of the connecting members includes an end which is fixed to at least an area where the expanding portion is laterally expanded. In this embodiment, when the expanding portion disposed in the end of the airbag is expanded in the expanded condition of he airbag, the end fixed to the expanding portion is laterally displaced so that a longitudinal length of the connecting member may be shortened to absorb its slack.
According another preferred embodiment of the invention, the slack absorbing device may include an expanding portion which is formed in at least one of the front and rear ends of the airbag and is expanded in the expanded condition of the airbag, a hole which is formed in the airbag positoned in the central direction more than the expanding portion with laterally penetrating the airbag, and at least one of the connecting members includes an end which is passed through the hole from either of the left and right sides of the expanding portion to the opposite side of the expanding portion and is fixed at the opposite side of the expanding portion with being wound around the opposite side of the expanding portion.
In this embodiment, when the expanding portion disposed in the end of the airbag is expanded in the expanded condition on the airbag, the end portion of the connecting member is rolled up by the expanding portion. Therefore, if a slack of the connecting member is relatively large, the slack is desirably absorbed so that a sufficient tension may be provided to the airbag. Since the tension provided from the connecting member to the airbag is dispersed over a surrounding area of the expanding portion to avoid a load concentration, a possible breakage of the airbag can be prevented.
According to a further preferred embodiment of the present invention, the slack absorbing device may be disposed between at least one of the connecting members and a body of the vehicle. In this embodiment, it is unnecessary to process the airbag for providing the slack absorbing device. Thus, the increased seams and complicated structure of the airbag caused from this processing can be avoided. As a result, possible deterioration of the occupant protection performance and increased cost of the airbag can be prevented.
In this embodiment, at least one of the connecting members may include a first end connected to the airbag and a second end connected to the body, the first end being disposed upward more than the second end in the housed condition of the airbag, and the slack absorbing device may include a guide member for guiding the at least one of the connecting members with making the at least one of the connecting members bend when the first end is moved downward in the expanded condition of the airbag.
Without the slack absorbing device, since the first end of the connecting member is located upward more than the second end of the connecting member when the airbag is housed and is moved downward in the expanded condition of the airbag, a distance between both the ends of the connecting member in the expansion of the airbag becomes shorter than that in the housed condition of the airbag, and this causes a slack of the connecting members. In this embodiment of invention, since the connecting member is guided by the guide member to make the connecting member bend when the first end of the connecting member is moved downward in the expanded condition of the airbag, the slack of the connecting member can be absorbed.
In this preferred embodiment, the guide member may include a bank portion for pushing the at least one of the connecting members in the inward direction with respect to a compartment of the vehicle in the expanded condition of the airbag. This causes the connecting members to be pushed and bent by the bank portion in the middle of the expansion of the airbag. Thus a slack of the connecting members can be absorbed. In addition, since the airbag is wholly pushed in the inward direction with respect to a compartment through the connecting members, the occupant restraint performance can be enhanced.
According to another preferred embodiment of the present invention, wherein the connecting member may include an end connected to the airbag side, the end of the connecting member being sewn to the airbag at or in the vicinity of a seam of the airbag. In this embodiment, even when the end of the connecting member is sewn to the airbag in the vicinity of the seams, no deterioration of the shock absorbing performance of the airbag is caused because of a primitively low shock absorbing performance of the airbag near the seams. Further, when the connecting member is sewn to the airbag precisely at the seam, the strength reduction of the airbag caused from the sewing can be avoided.
According to a further preferred embodiment of the present invention, each of the front and rear connecting members may be housed between a pillar of the body and an interior member of the pillar in the housed condition of the airbag. This improves the commercial value since the connecting members are hidden behind the interior member.
According to a still further embodiment of the present invention, the vehicle may include: a plurality of seats disposed longitudinally, the plurality of seats having a front seat and a rear seat positioned rearward with respect to the front seat; a front pillar positioned at a forward position relative to the front seat; and a quarter pillar extending from the vicinity of the lateral side of the rear seat to the rear of the rear seat, wherein the front side pillar may be the front pillar, the rear side pillar may be the quarter pillar and wherein the airbag may be expanded to cover a side window disposed between the front pillar and the quarter pillar. In this embodiment, the airbag can be extremely widely extended in the longitudinal direction. Generally, when the length in the longitudinal direction is increased, the occupant restraint performance in the lateral direction naturally tends to be reduced. Therefore, absorbing the slack of the connecting member to provide a sufficient tension to the airbag can be quite effective to enhance the occupant restraint performance.
According to another aspect of the invention, there is provided, in addition to one expansion area to be expanded to cover the side window, another airbag expansion area which is located on a rear side of the expansion area and is expanded over the rear pillar positioned on a side of a compartment of the vehicle, so that the impact at the time when an occupant collides with the rear pillar can be absorbed.
Particularly, in an occupant protection device for a vehicle, wherein the vehicle includes: a front pillar and a rear pillar disposed on a front and rear sides of a side window of the vehicle respectively, the front and rear pillars being extended approximately vertically along the front and rear edges of the side window respectively; and a roof rail extended in the longitudinal direction of the vehicle to connect respective upper ends of the front and rear pillars, the occupant protection device comprises: an airbag including a first expansion area which is housed along at least the roof rail and is expanded into a compartment of the vehicle to cover the side window when an impact load is acted on a side of the vehicle; and a connecting member connected between a rear portion of the first expansion area of the airbag and a body of the vehicle positioned on a rear side of the first expansion area for providing a longitudinal tension to a lower portion of the airbag in the expansion of the airbag, wherein the airbag includes a second expansion area which is expanded rearward more than a fixing portion where the connecting member is fixed to the airbag.
According to the structure described above, in the case where and the airbag is expanded when an impact load is acted on the side of the vehicle, the first expansion area is expanded to cover the side window of the vehicle, and at the same time the longitudinal tension is provided to the lower portion of the airbag by the connecting member which is connected between the rear end of the first expansion area and the vehicle body. Thus, the impact at the time when an occupant secondarily collides with a window glass can be absorbed, or the occupant can be prevented from being thrown out of the window.
In addition, since the second expansion area of the airbag is expanded to be disposed rearward more than the fixing portion where the connecting member is fixed to the airbag, the impact at the time when an occupant secondarily collides with a body member of the vehicle in an area positioned rearward more than the fixing portion where the connecting member is fixed to the airbag, for example the rear pillar disposed on the rear side of the window, can be absorbed and mitigated by the second expansion area. Since the second expansion area is expanded rearward more than the fixing portion where the connecting member is fixed to the airbag and accordingly is a soft area where no tension is provided by the connecting member, the second expansion area provides an impact absorbing characteristic superior to that of the first expansion area where the tension by the connecting member is provided. Thus the impact on the occupant can be surely absorbed.
According to still another aspect of the present invention, in occupant protection device for a vehicle, wherein the vehicle includes: a front pillar and a rear pillar disposed on a front and rear sides of a side window of the vehicle respectively, the front and rear pillars being extended approximately vertically along the front and rear edges of the side window respectively; and a roof rail extended in the longitudinal direction of the vehicle to connect respective upper ends of the front and rear pillars, as same as the first invention, the occupant protection device comprises; an airbag including a first expansion area which is housed along at least the roof rail and is expanded into a compartment of the vehicle to cover the side window when an impact load is acted on a side of the vehicle; and a connecting member connected between a rear end of the airbag and a body of the vehicle positioned on a rear side of the airbag for providing a longitudinal tension to a lower portion of the airbag in the expansion of the airbag, wherein the airbag includes a second expansion area which is expanded into a compartment of the vehicle positioned rearward more than an exit portion through which the first expansion area is expanded into the compartment of the vehicle.
According to the structure described above, since the second expansion area is expanded into the compartment of the vehicle positioned rearward more than the exit through which the first expansion area is expanded into the compartment of the vehicle to cover the side window in the expansion of the airbag, the impact on the occupant at the time when the occupant secondarily collides with the rear pillar positioned on the rear side of the window can be absorbed and mitigated by the second expansion area.
In a preferred embodiment of the present invention, the second expansion area of the airbag is adapted to be expanded to cover at least a part of the rear pillar. This invention provides the same effect as the first invention.
In another preferred embodiment of the present invention, the rear pillar may be adapted to dispose on a side of an occupant seated on a rear seat of the vehicle; and the second expansion area of the airbag may be adapted to be expanded to overlap with the rear pillar when viewed from a side of the vehicle. Thus the reaction force at the time when an occupant collides with the rear pillar after the side impact is acted on the body ob the vehicle can be received by the rear pillar to surely absorb the impact.
In further embodiment of the present invention, a rear pillar trim may be provided to cover the rear pillar positioned on a side of a compartment of the vehicle, wherein a rear end portion of the first expansion area of the airbag, the second expansion area of the airbag and the connecting member are housed at least in the rear pillar trim and may be adapted to be expanded with running out from a front end of the rear pillar trim to an outside of the rear pillar trim in the expanded condition of the airbag. Thus, the airbag can be housed with excellent appearance of the vehicle interior since the airbag to be expanded at the front side and rear side of the front end of the rear trim can be hidden behind the trim when the airbag is in its housed condition.
In still another embodiment of the present invention, the second expansion area of the airbag may be adapted to be expanded earlier than the first expansion area. According to the above structure, the occupant can be surely protected further even when the rear pillar is protruded more toward the inside of the compartment of the vehicle comparing with the window and is located closer to the occupant, because the second expansion area positioned corresponding to the rear pillar is expanded earlier than the first expansion area positioned corresponding to the window.